Light converter and light source unit, and projector

ABSTRACT

The invention aims to provide small-sized and highly-reliable light converter and light source unit, as well as a projector each of which makes it possible to cool down heat generated in a fluorescent body in a motorless manner. A light converter of the disclosure includes: a fluorescent body (12) that is excited by excitation light; a first light-collecting lens (11A) that has a lens surface to which the fluorescent body is bonded, and causes the excitation light to enter the fluorescent body; and a heat-dissipating member (14) to which the lens surface is adhered at least around a region to which the fluorescent body is bonded.

TECHNICAL FIELD

The disclosure relates to a light converter and a light source unit, aswell as a projector each of which includes a fluorescent body thatconverts a light wavelength.

BACKGROUND ART

In recent years, a product has increased in number that adopts asolid-state light-emitting device such as a light-emitting diode (LightEmitting Diode; LED) and a laser diode (Laser Diode; LD) instead of acurrently-available high-pressure mercury lamp, a xenon lamp, etc. for alight source in use for a projector, etc. for presentation or digitalcinema. The solid-state light-emitting device such as the LED is moreadvantageous than a discharge lamp in terms of not only size and powerconsumption but also high reliability. In particular, to achieve furtherenhanced luminance and lowered power consumption, it is effective toimprove the light use efficiency with use of the LD that serves as apoint light source.

As a projector with use of the LD for a light source, a projector hasbeen developed that utilizes fluorescent light generated in a manner ofexciting a fluorescent body that is formed as a film on a rotating baseusing a laser beam emitted from the LD. In such a projector, it isnecessary to suppress rise in temperature in consideration oftemperature characteristics in the optical conversion efficiency of thefluorescent body, and thermal resistance of a binder, etc. for formingthe fluorescent body on the base. Therefore, for example, PTL 1discloses a projector that provides accommodation for a fluorescentwheel unit in which a fluorescent layer is formed, and a fluorescentwheel that is rotary-driven by a motor is attached, and a blower fanthat blows cooling air to a light-emitting section of the fluorescentlayer in a sealed container. The sealed container is provided with anair-circulating pathway in such a manner that the air from the blowerfan flows through the light-emitting section of the fluorescent wheel.

Further, PTL 2 and PTL 3 propose a non-rotating method that performsheat dissipation of the fluorescent body with use of a heat sink withoutrotating the fluorescent wheel. For example, the PTL 2 proposes astructure in which a spacer and the fluorescent body are disposed on asubstrate with the heat sink provided on a back surface thereof, and thespacer and the fluorescent body are bonded in a state of beinginterposed between the substrate and a light-collecting lens in aplano-convex shape that collects excitation light. Further, PTL 3proposes a structure that seals the fluorescent body disposed on thesubstrate by a light-collecting lens in a meniscus shape.

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication No. 2014-92599

PTL 2: Japanese Unexamined Patent Application Publication No.2014-165058

PTL 3: Japanese Unexamined Patent Application Publication No.2014-123014

SUMMARY OF THE INVENTION

In the above-described method of rotating the fluorescent wheel by amotor, it may be possibly necessary to take account of generation ofnoise caused by rotation, and a lifetime of the motor. Further, a methodin which the air intervenes between the fluorescent body and thelight-collecting lens has been general; however, it is likely that sucha method will necessitate a structure that performs dust-proof ofcooling of the fluorescent body to avoid deterioration in thereliability due to adherence of dust. This may possibly cause anincrease in the size of a cooling system.

In contrast, the non-rotating method involves fewer issues with thenoise and lifetime. However, such a method makes it difficult to enhancethe luminance due to more increased temperature caused by heatgeneration of the fluorescent body in comparison with the rotatingmethod, a decrease in the optical conversion efficiency, anddeterioration in the fluorescent body or an adhesive material. Forexample, in the structures described in the PTL 2 and PTL 3, an airlayer is interposed between the light-collecting lens closest to thefluorescent body and the substrate at least in a peripheral region ofthe fluorescent body, which may possibly cause degradation in the heatdissipation capability.

It is desirable to provide a small-sized and highly-reliable lightconverter and light source unit, as well as a projector each of whichmakes it possible to cool down heat generated in the fluorescent body ina motorless manner.

A light converter according to one embodiment of the disclosureincludes: a fluorescent body that is excited by excitation light; afirst light-collecting lens that has a lens surface to which thefluorescent body is bonded, and causes the excitation light to enter thefluorescent body; and a heat-dissipating member to which the lenssurface is adhered at least around a region to which the fluorescentbody is bonded.

A light source unit according to one embodiment of the disclosureincludes: a light converter; and a light source section that emitsexcitation light toward the light converter. The light converterincludes: a fluorescent body that is excited by excitation light; afirst light-collecting lens that has a lens surface to which thefluorescent body is bonded, and causes the excitation light to enter thefluorescent body; and a heat-dissipating member to which the lenssurface is adhered at least around a region to which the fluorescentbody is bonded.

A projector according to one embodiment of the disclosure includes: alight source unit that has a light converter, and a light source sectionthat emits excitation light toward the light converter; and animage-generating section that generates an image on the basis of lightemitted from the light source unit. The light converter includes: afluorescent body that is excited by excitation light; a firstlight-collecting lens that has a lens surface to which the fluorescentbody is bonded, and causes the excitation light to enter the fluorescentbody; and a heat-dissipating member to which the lens surface is adheredat least around a region to which the fluorescent body is bonded.

In the light converter or the light source unit, or the projectoraccording to the embodiment of the disclosure, the fluorescent body isbonded to the lens surface of the first light-collecting lens thatcauses the excitation light to enter the fluorescent body. The lenssurface to which the fluorescent body is bonded is adhered to theheat-dissipating member at least around the region to which thefluorescent body is bonded.

According to the light converter or the light source unit, or theprojector of the embodiment of the disclosure, the fluorescent body isbonded to the lens surface of the first light-collecting lens, and atleast a peripheral region of the region to which the fluorescent body isbonded in the lens surface to which the fluorescent body is bonded isadhered to the heat-dissipating member, which makes it possible to cooldown heat generated in the fluorescent body in a motorless manner,thereby allowing for reduced size and improved reliability.

It is to be noted that the effects described above are not necessarilylimitative, and any of effects described in the disclosure may beprovided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a configuration diagram illustrating an example of a projectoraccording to a first embodiment of the disclosure.

FIG. 2 is a configuration diagram illustrating an example of a lightsource unit according to the first embodiment.

FIG. 3 is a cross-sectional view of an example of a light converteraccording to the first embodiment.

FIG. 4 is an enlarged cross-sectional view of a configuration example ofa major part of the light converter according to the first embodiment.

FIG. 5 is a cross-sectional view of an example of a manufacturingprocess of the light converter according to the first embodiment.

FIG. 6 is a cross-sectional view of a first configuration example of alight converter according to a second embodiment.

FIG. 7 is a cross-sectional view of a second configuration example ofthe light converter according to the second embodiment.

FIG. 8 is a cross-sectional view illustrating a modification example ofthe second configuration example of the light converter according to thesecond embodiment.

FIG. 9 is a cross-sectional view of a third configuration example of thelight converter according to the second embodiment.

FIG. 10 is a cross-sectional view of an example of a light converteraccording to a third embodiment.

FIG. 11 is a cross-sectional view of an example of a light converteraccording to a fourth embodiment.

MODES FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the disclosure are described in detail withreference to the drawings. It is to be noted that the description isgiven in the following order.

1. First Embodiment 1.1 Configuration 1.1.1 Configuration Example ofProjector (FIG. 1) 1.1.2 Configuration Example of Light Source Unit(FIG. 2)

1.1.3 Configuration Example of Light Converter (reflective lightconverter) (FIGS. 3 to 5)

1.2 Workings and Effects

2. Second Embodiment (reflective light converter)

2.1 First Configuration Example (FIG. 6) 2.2 Second ConfigurationExample (FIGS. 7 and 8) 2.3 Third Configuration Example (FIG. 9)

3. Third Embodiment (reflective and liquid-cooled light converter) (FIG.10)4. Fourth Embodiment (transmissive light converter) (FIG. 11)

5. Other Embodiments 1. First Embodiment 1.1 Configuration 1.1.1Configuration Example of Projector

FIG. 1 illustrates a configuration example of a projector according to afirst embodiment of the disclosure.

A projector 1 according to the present embodiment includes a lightsource unit 100; an image-generating system 400 that generates an imageon the basis of light emitted from the light source unit 100; and aprojection optical system 600. The image-generating system 400 has animage-generating section that generates an image on the basis of appliedlight, and an illuminating optical system 420 that irradiates theimage-generating section with the light emitted from the light sourceunit 100.

The image-generating section has a light valve 410R for red, a lightvalve 410G for green, a light valve 410B for blue, and a dichroic prism540 that synthesizes light from each of the light valves 410R, 410G and410B. Each of the light valves 410R, 410G and 410B includes, forexample, a transmissive liquid crystal display device.

The projection optical system 600 serves to project images generated inthe image-generating section on an unillustrated screen, and has aplurality of lenses 610.

The illuminating optical system 420 has an integrator device 430, apolarization converter device 440, a light-collecting lens 450, dichroicmirrors 460 and 470, mirrors 480, 490, and 500, relay lenses 510 and520, and field lenses 530R, 530G and 530B.

The integrator device 430 includes a first fly-eye lens 431 and a secondfly-eye lens 432. The first fly-eye lens 431 has, for example, aplurality of microlenses that are two-dimensionally arrayed. The secondfly-eye lens 432 has, for example, a plurality of microlenses that arearrayed in a manner of corresponding to each of the microlenses of thefirst fly-eye lens 431.

As a whole, the integrator device 430 has a function of adjustingentrance light with which the polarization converter device 440 isirradiated by the light source unit 100 to the uniform luminancedistribution. The light entering the integrator device 430 from thelight source unit 100 is, for example, parallel light of white light Lw.The parallel light from the light source unit 100 is split into aplurality of bundles of ray by the plurality of microlenses of the firstfly-eye lens 431. Each of the split bundles of ray is image-formed onthe corresponding microlens in the second fly-eye lens 432. Each of theplurality of microlenses of the second fly-eye lens 432 functions as asecondary light source. The plurality of luminance-matched parallellight beams are emitted from the plurality of microlenses of the secondfly-eye lens 432 as entrance light incoming into the polarizationconverter device 440.

The polarization converter device 440 has a function of matching apolarization state of entrance light incoming through the integratordevice 430. The light-collecting lens 450 outputs exit light includingblue light B3, green light G3, and red light R3 through the polarizationconverter device 440.

The dichroic mirrors 460 and 470 have properties of selectivelyreflecting color light at a predetermined wavelength band, andtransmitting light at any other wavelength band. For example, thedichroic mirror 460 reflects the red light R3 selectively. The dichroicmirror 470 reflects the green light G3 selectively between the greenlight G3 and the blue light B3 that pass through the dichroic mirror460. The remaining blue light B3 passes through the dichroic mirror 470.In such a manner, the white light Lw emitted from the light source unit100 is separated into a plurality of color light beams of differentcolors.

The separated red light R3 is parallelized in a manner of beingreflected by the mirror 480 to pass through the field lens 530R, andthereafter enters the light valve 410R for modulation of the red lightR3. The green light G3 is parallelized in a manner of passing throughthe field lens 530G, and thereafter enters the light valve 410G formodulation of the green light G3. The blue light B3 passes through therelay lens 510 to be reflected by the mirror 490, and further passesthrough the relay lens 520 to be reflected by the mirror 500. The bluelight B3 reflected by the mirror 500 is parallelized in a manner ofpassing through the field lens 530B, and thereafter enters the lightvalve 410B for modulation of the blue light B3.

Each of the light valves 410R, 410G, and 410B is electrically coupled toa signal source such as an unillustrated image reproducer that suppliesan image signal including image information. Each of the light valves410R, 410G, and 410B modulates entrance light on each pixel basis togenerate an image of each color on the basis of the supplied imagesignal of each color. More specifically, the light valve 410R generatesa red image. The light valve 410G generates a green image. The lightvalve 410B generates a blue image. The modulated light of each colorimage enters the dichroic prism 540 to be synthesized. The dichroicprism 540 synthesizes the light beams of respective color imagesincoming from three directions by superimposing such light to emit theresultant light toward the projection optical system 600.

The projection optical system 600 applies light of the image synthesizedby the dichroic prism 540 on an unillustrated screen. In such a manner,a full-color image is displayed.

1.1.2 Configuration Example of Light Source Unit

FIG. 2 illustrates a configuration example of the light source unit 100.

The light source unit 100 includes a light converter 10, and a lightsource section 20 that emits excitation light toward the light converter10. The light source section 20 has a light source 210, light-collectingmirrors 211A and 211B, as well as a light-collecting mirror 212, adichroic mirror 213, a blue light source optical system 214, and alight-collecting lens 215.

As detailed later, the light converter 10 has a first light-collectinglens 11A and a second light-collecting lens 11B, as well as afluorescent body 12 that is excited by excitation light.

The light source 210 is configured to include, for example, a blue LDthat is able to oscillate blue light Lb1 having a peak wavelength ofemission intensity within the wavelength range of 400 nm to 500 nm, forexample. The blue light source optical system 214 is also configured toinclude a blue LD that is able to oscillate blue light Lb2, for example.As an alternative to the LD, any other light source such as an LED maybe used for the light source 210 and the blue light source opticalsystem 214.

The light-collecting mirrors 211A and 211B, as well as thelight-collecting mirror 212 are optical systems that serve to output theblue light Lb1 emitted from the light source 210 as excitation lighttoward the light converter 10.

The blue light source optical system 214 outputs the blue light Lb2 tobe used for generating the white light Lw in a manner of performingsynthesis with yellow light Ly outgoing from the light converter 10. Thedichroic mirror 213 and the light-collecting lens 215 are opticalsystems that generate the white light Lw by synthesizing the yellowlight Ly and the blue light Lb2 to output the resultant light to theoutside.

Each of the light-collecting mirrors 211A and 211B has a concavereflective surface that substantially parallelizes a bundle of ray ofthe blue light Lb1 emitted from the light source 210, and focuses such abundle of ray onto the light-collecting mirror 212. The light-collectingmirror 212 reflects the blue light Lb1 focused by the light-collectingmirrors 211A and 211B toward the light converter 10.

The dichroic mirror 213 has the properties of selectively reflectingcolor light in a predetermined wavelength band, and transmitting lightin any other wavelength band. More specifically, the dichroic mirror 213transmits the blue light Lb1 emitted from the light source 210 and theblue light Lb2 outgoing from the blue light source optical system 214,and reflects the yellow light Ly that is subjected to optical conversionfrom the blue light Lb1 in the light converter 10.

The fluorescent body 12 is excited in such a manner that the fluorescentbody 12 is irradiated with the blue light Lb1 passing through thedichroic mirror 213 through the first light-collecting lens 11A and thesecond light-collecting lens 11B in the light converter 10. The excitedfluorescent body 12 converts the blue light Lb1 serving as excitationlight into the yellow light Ly in a wavelength band including awavelength band range from a red wavelength band to a green wavelengthband as a fluorescent component, for example. The yellow light Ly isreflected by the dichroic mirror 213 toward the light-collecting lens214. Further, the blue light Lb2 outgoing from the blue light sourceoptical system 214 passes through the dichroic mirror 213 to traveltoward the light-collecting lens 214. The white light Lw is generated insuch a manner that the blue light Lb2 and the yellow light Ly aresynthesized.

1.1.3 Configuration Example of Light Converter

FIG. 3 illustrates a configuration example of the light converter 10.FIG. 4 illustrates an enlarged view of a configuration example of amajor part of the light converter 10.

The light converter 10 has the first light-collecting lens 11A, thesecond light-collecting lens 11B, the fluorescent body 12, a heat sink13, a heat spreader 14, and a lens holder 15. Between the firstlight-collecting lens 11A as well as the fluorescent body 12 and theheat spreader 14, a reflective layer 21 and an adhesive layer 22 may beformed, as illustrated in FIG. 4.

In the light converter 10, the second light-collecting lens 11B and thefirst light-collecting lens 11A are disposed in order of entrance ofexcitation light. The first light-collecting lens 11A has apredetermined lens surface to which the fluorescent body 12 is bonded.The first light-collecting lens 11A focuses the excitation lightincoming through the second light-collecting lens 11B onto thefluorescent body 12. Further, the first light-collecting lens 11Aoutputs a fluorescent component from the fluorescent body 12 toward thesecond light-collecting lens 11B. A lens material of the firstlight-collecting lens 11A desirably has a refractive index closer tothat of the fluorescent body 12 to allow the fluorescent component fromthe fluorescent body 12 to be captured efficiently. In addition, thelens material of the first light-collecting lens 11A is desirably amaterial that is able to efficiently diffuse heat generated from thefluorescent body 12. For such reasons, the first light-collecting lens11A is desirably a sapphire lens, for example.

The second light-collecting lens 11B focuses the excitation light fromthe light source section 20 toward the first light-collecting lens 11A.Further, the second light-collecting lens 11B focuses the fluorescentcomponent from the fluorescent body 12 that is incoming through thefirst light-collecting lens 11A toward the light source section 20. Thesecond light-collecting lens 11B is, for example, greater in an outerdiameter than the first light-collecting lens 11A, and an outercircumferential portion thereof is held by the lens holder 15.

It is to be noted that FIG. 3 illustrates a configuration example ofusing the two light-collecting lenses. However, the configuration is notlimited to such an example, and the use of the three or morelight-collecting lenses may be acceptable.

All of the fluorescent body 12 and a region other than a region to whichthe fluorescent body 12 is bonded in the predetermined lens surface ofthe first light-collecting lens 11A are desirably adhered to aheat-dissipating member with a thermally-conductive layer in between. Ina configuration example illustrated in FIG. 4, the reflective layer 21is able to function as the thermally-conductive layer. Further, the heatspreader 14 is able to function as the heat-dissipating member. Further,the adhesive layer 22 may be provided between the reflective layer 21and the heat spreader 14.

Each of the heat sink 13 and the heat spreader 14 has a function as theheat-dissipating member that diffuses heat generated in the fluorescentbody 12 to lower the temperature. Further, the heat spreader 14 has afunction of lowering the temperature of the first light-collecting lens11A. The heat sink 13 is provided on a back surface of the heat spreader14. The heat sink 13 has a function of transferring the heat diffused bythe heat spreader 14 to the air for heat dissipation. Each of the heatsink 13 and the heat spreader 14 is made of a material havingrelatively-high thermal conductivity through a metallic or ceramicmaterial. For example, each of the heat sink 13 and the heat spreader 14is made of copper, aluminum, sapphire, or molybdenum.

The lens holder 15 serves to position and hold the secondlight-collecting lens 11B. The lens holder 15 may be integrated with theheat spreader 14.

The first light-collecting lens 11A and the second light-collecting lens11B are disposed with spacing in between. This results in space 16 beingformed between the first light-collecting lens 11A and the secondlight-collecting lens 11B. The space 16 is desirably of a dust-proofstructure that prevents intrusion of dust from the outside. For example,a sealed structure is desirably adopted that covers a portion of a topsurface of the heat spreader 14 and an outer circumferential portion ofthe second light-collecting lens 11B with the lens holder 15.

The fluorescent body 12 is excited by the blue light Lb1 serving asexcitation light from the light source section 20 to emit light in awavelength band that is different from a wavelength of the excitationlight. The fluorescent body 12 includes, for example, a fluorescent bodymaterial that is excited by the blue light Lb1 having a centerwavelength of about 445 nm to emit fluorescent light, and outputs lightobtained by converting a portion of the blue light Lb1 into the yellowlight Ly, as a fluorescent component. As the fluorescent body materialcontained in the fluorescent body 12, for example, a YAG (yttriumaluminum garnet)-based fluorescent body is used. It is to be noted thata type of the fluorescent body material, a wavelength band of light tobe excited, and a wavelength band of visible light generated byexcitation are not limited to those described above.

The fluorescent body 12 is a solid substance of a polycrystalline orsintered body that performs wavelength conversion of the excitationlight. The fluorescent body 12 may be formed, for example, in such amanner that a substrate is coated with a powdered fluorescent bodymaterial. As an alternative, the fluorescent body 12 may be made byhardening a fluorescent body material with use of an inorganic material.Further alternatively, the fluorescent body 12 may be formed byprocessing the fluorescent body material with use of a crystallinematerial, or by sintering the fluorescent body material. As long as thefluorescent body 12 has a function of converting a wavelength of lightinto a wavelength other than a wavelength of the excitation light, theform thereof is not limited to any of the forms described above.

A planar size of the fluorescent body 12 may be, for example, one fifthor less of an outer diameter of the first light-collecting lens 11A. Aside surface of the fluorescent body 12 may have a sloped shape, asillustrated in FIG. 4. With such a shape, as illustrated in FIG. 4, asize of the surface of the fluorescent body 12 on the side of beingbonded to the first light-collecting lens 11A may be greater than a sizeof the surface of the fluorescent body 12 on the side of the heatspreader 14.

A junction 23 between the fluorescent body 12 and the predetermined lenssurface in the first light-collecting lens 11A has a function ofreducing an optical loss between the fluorescent body 12 and the firstlight-collecting lens 11A, and promoting heat dissipation. Thefluorescent body 12 and the predetermined lens surface in the firstlight-collecting lens 11A are desirably bonded directly to each otherwith a thin film in between without having an adhesive layer betweenthem. As a bonding method, a method of non-use of an adhesive material,such as normal-temperature bonding and optical contact, for example, isusable.

The reflective layer 21 serves to enhance the extraction efficiency oflight from the fluorescent body 12. The area of the reflective layer 21is desirably greater than the area of the fluorescent body 12.Specifically, the reflective layer 21 is desirably provided not only ina region of the fluorescent body 12, but also over a region on theoutside of the fluorescent body 12. At the minimum, in such a mannerthat the reflective layer 21 is formed as far as a region between thefluorescent body 12 and the heat spreader 14, as well as a region arounda region to which the fluorescent body 12 is bonded in the predeterminedlens surface of the first light-collecting lens 11A, it is possible toreduce warming in the vicinity of the junction 23 and the heat spreader14 due to excitation light. Further, this makes it possible to preventlight deterioration of the junction 23 that is caused by the excitationlight.

FIG. 5 illustrates an example of a manufacturing process of the lightconverter 10.

First, as illustrated on the upper side of FIG. 5, the fluorescent body12 is positioned and bonded at a predetermined location of the firstlight-collecting lens 11A, for example, at a central portion of thepredetermined lens surface. For example, in a case where the firstlight-collecting lens 11A is configured as a lens in a plano-convexshape, a lens surface served as a planar surface is desirably used asthe predetermined lens surface. As a bonding method, bonding isperformed with use of, for example, the normal-temperature bonding orthe optical contact.

Next, as illustrated on the middle of FIG. 5, the reflective layer 21 isformed on the surface of the fluorescent body 12, and at least around aregion to which the fluorescent body 12 is bonded in the predeterminedlens surface of the first light-collecting lens 11A. As the reflectivelayer 21, for example, an Ag film is formed with use of vapordeposition.

Thereafter, as illustrated on the lower side of FIG. 5, the firstlight-collecting lens 11A and the fluorescent body 12 in both of whichthe reflective layer 21 is formed on the surfaces thereof are adhered tothe heat spreader 14 with the adhesive layer 22 in between. As theadhesive layer 22, for example, an adhesive material with high thermalconductivity, such as an Ag paste is usable.

1.3 Workings and Effects

As described above, according to the present embodiment, the fluorescentbody 12 is bonded to the predetermined lens surface of the firstlight-collecting lens 11A, and all of the fluorescent body 12 and theregion other than the region to which the fluorescent body 12 is bondedin the predetermined lens surface to which the fluorescent body 12 isbonded are adhered to the heat spreader 14 serving as theheat-dissipating member. This makes it possible to cool down the heatgenerated in the fluorescent body 12 in a motorless manner, allowing forachievement of reduced size and improved reliability.

According to the present embodiment, the fluorescent body 12 is directlybonded to the first light-collecting lens 11A that focuses excitationlight, which allows the heat-dissipating performance of the fluorescentbody 12 to be improved. Further, the fluorescent body 12 is directlybonded to the first light-collecting lens 11A, which makes it possibleto reduce internal reflection of the light emitted from the fluorescentbody 12 on an interfacial surface, and to enhance the light extractionefficiency. This makes it possible to reduce heat generation itself ofthe fluorescent body 12 that occurs at the time of obtaining theidentical luminance.

Further, according to the present embodiment, the reflective layer 21 isprovided between the first light-collecting lens 11A and the adhesivelayer 22, which makes it possible to reduce rise in temperature of thefluorescent body 12, and to improve the reliability of a thermal contactlayer. The first light-collecting lens 11A and the fluorescent body 12are adhered to the heat spreader 14 with the high thermal conductivity,allowing the heat-dissipating performance to be raised.

In addition, according to the present embodiment, the fluorescent body12 is directly bonded to the first light-collecting lens 11A thatfocuses the excitation light, and further a dust-proof structure isadopted for the space 16 that is interposed between the firstlight-collecting lens 11A and the second light-collecting lens 11B,making it possible to achieve a small-sized and highly-reliablefluorescent body cooling system.

It is to be noted that the effects described herein are merelyexemplified and non-limiting, and other effects may be provided. Thesame is true for the following other embodiments.

2. Second Embodiment

Next, a description is provided of a second embodiment of thedisclosure. Hereinafter, for parts having configurations and workingssimilar to those in the above-described first embodiment, the relateddescriptions are omitted as appropriate.

In the light converter 10 in the above-described first embodiment, allof the regions other than the region to which the fluorescent body 12 isbonded in the predetermined lens surface of the first light-collectinglens 11A are adhered to the heat spreader 14 serving as theheat-dissipating member. However, only a peripheral region of the regionto which the fluorescent body 12 is bonded may be partially adhered tothe heat spreader 14. With reference to FIGS. 6 to 9, a description isprovided below of examples of such an adhesive structure.

It is to be noted that basic configurations of a projector and a lightsource unit according to the present embodiment may be substantiallysimilar to those of the above-described first embodiment.

2.1 First Configuration Example

FIG. 6 illustrates a first configuration example of a light converteraccording to the second embodiment of the disclosure.

In a light converter 10A, the heat spreader 14 is provided with astepped part 17 in a convex shape. The fluorescent body 12, and thepredetermined lens surface around the region to which the fluorescentbody 12 is bonded in the first light-collecting lens 11A are adhered tothe stepped part 17 of the heat spreader 14 with the reflective layer 21and the adhesive layer 22 in between. Adhesion of only the fluorescentbody 12 and a peripheral region of the fluorescent body 12 to the heatspreader 14 achieves the effect of the increased reliability in a casewhere a difference in the coefficient of thermal expansion between theheat spreader 14 and the first light-collecting lens 11A is large.

Other configurations may be substantially similar to those of the lightconverter 10 according to the above-described first embodiment.

2.2 Second Configuration Example

FIG. 7 illustrates a second configuration example of the light converteraccording to the second embodiment of the disclosure. Further, FIG. 8illustrates a modification example of the configuration example in FIG.7.

In a light converter 10B illustrated in FIG. 7, and a light converter10B′ illustrated in FIG. 8, the heat spreader 14 is provided with thestepped part 17 in a convex shape, as with the light converter 10Adescribed above. Further, the fluorescent body 12, and the predeterminedlens surface around the region to which the fluorescent body 12 isbonded in the first light-collecting lens 11A are adhered to the steppedpart 17 of the heat spreader 14 with the reflective layer 21 and theadhesive layer 22 in between.

In these light converters 10B and 10B′, the first light-collecting lens11A does not have a plano-convex shape, and the predetermined lenssurface to which the fluorescent body 12 is bonded has asubstantially-convex shape. A region outside a region adhered to thestepped part 17 in the predetermined lens surface of the firstlight-collecting lens 11A may be in a planar shape 18 that is slopedobliquely as in the light converter 10B illustrated in FIG. 7, or may bein a convex curved surface shape 18A as a whole as in the lightconverter 10B′ illustrated in FIG. 8.

Other configurations may be substantially similar to those of the lightconverter 10 according to the above-described first embodiment.

2.3 Third Configuration Example

FIG. 9 illustrates a third configuration example of the light converteraccording to the second embodiment of the disclosure.

In a light converter 10C, the heat spreader 14 is provided with thestepped part 17 in a convex shape, as with the light converter 10Adescribed above. Further, the fluorescent body 12, and the predeterminedlens surface around the region to which the fluorescent body 12 isbonded in the first light-collecting lens 11A are adhered to the steppedpart 17 of the heat spreader 14 with the reflective layer 21 and theadhesive layer 22 in between.

Further, in the light converter 10C, in a region on outside the steppedpart 17 in the heat spreader 14, a positioning section 19 is providedthat is directed to positioning of the first light-collecting lens 11Arelative to the heat spreader 14. The positioning section 19 ispartially in a concave shape. Thereby, the first light-collecting lens11A is positioned, resulting in the fluorescent body 12 beingpositioned.

Other configurations may be substantially similar to those of the lightconverter 10 according to the above-described first embodiment.

3. Third Embodiment

Next, a description is provided of a third embodiment of the disclosure.For parts having configurations and workings similar to those in theabove-described first embodiment and the above-described secondembodiment, the descriptions are omitted as appropriate below.

FIG. 10 illustrates a configuration example of a light converter 10Daccording to the third embodiment of the disclosure.

In the light converter 10 in the above-described first embodiment, thesealed structure is adopted for the space 16 between the firstlight-collecting lens 11A and the second light-collecting lens 11B. Incontrast, in the light converter 10D according to the presentembodiment, the lens holder 15 is provided with a passage hole throughwhich a liquid coolant 24 passes, and a structure is adopted in whichthe liquid coolant 24 passes through the space 16 between the firstlight-collecting lens 11A and the second light-collecting lens 11B.Further, a structure may be adopted in which the liquid coolant 24passes through a portion of the heat sink 13 as well.

The liquid coolant 24 is desirably, for example, a liquid such assilicon oil that exhibits high transmittance, and has a freezing pointof −20 degrees centigrade or lower. The transmittance is desirably 95%or higher for visible light, for example. As a result, the use of theliquid coolant 24 makes it possible to cool the first light-collectinglens 11A and the heat spreader 14 more efficiently in a space-savingmanner, as compared with an air-cooling method.

Other configurations may be substantially similar to those of the lightconverter 10 according to the above-described first embodiment. Further,basic configurations of a projector and a light source unit according tothe present embodiment may be substantially similar to those of theabove-described first embodiment.

4. Fourth Embodiment

Next, a description is provided of a fourth embodiment of thedisclosure. For parts having configurations and workings similar tothose in the above-described first to third embodiments, thedescriptions are omitted as appropriate below.

FIG. 11 illustrates a configuration example of a light converter 10Eaccording to the fourth embodiment of the disclosure.

In the above-described first to third embodiments, the configurationexamples of the reflective light converter are adopted that each reflecta fluorescent component emitted from the fluorescent body 12 in theopposite direction to the entrance direction of excitation light. Incontrast, the light converter 10E according to the present embodiment isconfigured in such a manner that the fluorescent component and part ofthe excitation light pass through the fluorescent body 12 to be emittedout in the same direction.

The light converter 10E includes a third light-collecting lens 11C and afourth light-collecting lens 11D in addition to the firstlight-collecting lens 11A and the second light-collecting lens 11B. Thethird light-collecting lens 11C and the fourth light-collecting lens 11Dare disposed in the output direction of the fluorescent component andthe excitation light. The third light-collecting lens 11C and the fourthlight-collecting lens 11D are disposed with spacing in between. Thisresults in space 25 being formed between the third light-collecting lens11C and the fourth light-collecting lens 11D. The fourthlight-collecting lens 11D is, for example, greater in an outer diameterthan the third light-collecting lens 11C, and an outer circumferentialportion thereof is held by the lens holder 15.

In the present embodiment, it is possible to generate the white light Lwby synthesizing the yellow light Ly that is a fluorescent componentemitted from the fluorescent body 12 and the blue light Lb1 passingthrough the fluorescent body 12. The white light Lw is outputted to theilluminating optical system 420 in the projector 1 illustrated inFIG. 1. The third light-collecting lens 11C and the fourthlight-collecting lens 11D focus and output the fluorescent component andthe excitation light toward the illuminating optical system 420. In thiscase, the blue light Lb1 passing through the fluorescent body 12 isutilizable, which makes it possible to eliminate the blue light sourceoptical system 214 and the dichroic mirror 213 of the light sourcesection 20 in the configuration illustrated in FIG. 2, thereby allowingthe light source section 20 to be reduced in size.

In the light converter 10E, the third light-collecting lens 11C isdisposed to face the first light-collecting lens 11A with thefluorescent body 12 and the heat spreader 14 interposed between them.The fluorescent component emitted from the fluorescent body 12 andexcitation light enter the third light-collecting lens 11C. The thirdlight-collecting lens 11C has a predetermined lens surface bonded to anoutput surface of the fluorescent body 12. A lens material of the thirdlight-collecting lens 11C, and a bonding method of the fluorescent body12 in the third light-collecting lens 11C may be substantially similarto those of the first light-collecting lens 11A.

The third light-collecting lens 11C corresponds to one specific exampleof an “output-side lens” in the disclosure.

All of the regions other than the region to which the fluorescent body12 is bonded in the predetermined lens surface of the firstlight-collecting lens 11A and the predetermined lens surface of thethird light-collecting lens 11C are adhered to the heat spreader 14. Itis to be noted that, between a region other than the region to which thefluorescent body 12 is bonded in the predetermined lens surface of thefirst light-collecting lens 11A and the heat spreader 14, a reflectivelayer may be provided around the fluorescent body 12. Further, apositioning section that is directed to positioning of the firstlight-collecting lens 11A and the third light-collecting lens 11C may beprovided on the heat spreader 14.

Further, in the light converter 10E, the lens holder 15 is provided witha passage hole through which the liquid coolant 24 passes. Thereby, astructure is adopted in which the liquid coolant 24 passes through thespace 16 between the first light-collecting lens 11A and the secondlight-collecting lens 11B, and the space 25 between the thirdlight-collecting lens 11C and the fourth light-collecting lens 11D.

It is to be noted that other basic configurations of a projector and alight source unit according to the present embodiment may besubstantially similar to those of the above-described first embodiment.

5. Other Embodiments

The technology of the disclosure is not limited to the descriptions ofthe above-described respective embodiments, but various modificationsmay be made.

For example, in any of the light source units 100 in the above-describedfirst to third embodiments, the blue light source optical system 214that emits the blue light Lb2 to be synthesized with the yellow light Lythat is a fluorescent component emitted from the fluorescent body 12 isprovided in addition to the light source 210 that emits the blue lightLb1 serving as excitation light, and the white light Lw is generated bysynthesizing the yellow light Ly and the blue light Lb2 from the bluelight source optical system 214. However, a configuration in which theblue light source optical system 214 is not provided may be alsoadopted. For example, a configuration may be made in such a manner thatthe fluorescent component emitted from the fluorescent body 12 becomesthe white light Lw, and the blue light source optical system 214 may beomitted. In such a case, for example, the blue light Lb1 serving as theexcitation light may be 405 nm, and the fluorescent body 12 may be madeof a material derived from mixing of a YAG-based fluorescent body andanother material-based fluorescent body.

Further, the technology of the disclosure is applicable to not only theprojector, but also car headlights, special illumination, etc.

For example, the technology may be also configured as follows.

(1)

A light converter including:

a fluorescent body that is excited by excitation light;

a first light-collecting lens that has a lens surface to which thefluorescent body is bonded, and causes the excitation light to enter thefluorescent body; and

a heat-dissipating member to which the lens surface is adhered at leastaround a region to which the fluorescent body is bonded.

(2)

The light converter according to (1), further including a reflectivelayer that is formed at least between the fluorescent body and theheat-dissipating member, and around a region to which the fluorescentbody is bonded in the lens surface.

(3)

The light converter according to (2), further including an adhesivelayer that is formed between the reflective layer and theheat-dissipating member.

(4)

The light converter according to any one of (1) to (3), in which all ofthe fluorescent body and a region other than a region to which thefluorescent body is bonded in the lens surface are adhered to theheat-dissipating member.

(5)

The light converter according to any one of (1) to (3), in which

the heat-dissipating member has a stepped part in a convex shape, and

the fluorescent body and the lens surface around a region to which thefluorescent body is bonded are adhered to the stepped part.

(6)

The light converter according to (5), in which a region outside a regionadhered to the stepped part in the lens surface has a planar shape.

(7)

The light converter according to (5), in which a region outside a regionadhered to the stepped part in the lens surface has a curved surfaceshape.

(8)

The light converter according to (5), in which the heat-dissipatingmember further has a positioning section that performs positioning ofthe first light-collecting lens relative to the heat-dissipating memberin a region outside the stepped part.

(9)

The light converter according to any one of (1) to (8), furtherincluding

a second light-collecting lens that is greater in an outer diameter thanthe first light-collecting lens, and outputs the excitation light towardthe first light-collecting lens; and

a lens holder that holds the second light-collecting lens.

(10)

The light converter according to (9), in which the firstlight-collecting lens and the second light-collecting lens are disposedwith spacing in between, and space between the first light-collectinglens and the second light-collecting lens is structured to be sealed bythe lens holder and the heat-dissipating member.

(11)

The light converter according to (9), in which a structure is adopted inwhich the first light-collecting lens and the second light-collectinglens are disposed with spacing in between, and a liquid coolant passesthrough space between the first light-collecting lens and the secondlight-collecting lens.

(12)

The light converter according to any one of (1) to (11), in which aplanar size of the fluorescent body is one fifth or less of an outerdiameter of the first light-collecting lens.

(13)

The light converter according to any one of (1) to (12), in which thefluorescent body and the lens surface are bonded by normal-temperaturebonding or optical contact.

(14)

The light converter according to any one of (1), (8), and (10) to (13),further including an output-side lens that is disposed to face the firstlight-collecting lens with the fluorescent body and the heat-dissipatingmember interposed in between, that a fluorescent component emitted fromthe fluorescent body and the excitation light enter, and that has a lenssurface bonded to an output surface of the fluorescent body.

(15)

The light converter according to (14), in which all of regions otherthan a region to which the fluorescent body is bonded in the lenssurface of the first light-collecting lens and the lens surface of theoutput-side lens are adhered to the heat-dissipating member.

(16)

A light source unit including:

a light converter; and

a light source section that emits excitation light toward the lightconverter,

the light converter including

a fluorescent body that is excited by excitation light,

a first light-collecting lens that has a lens surface to which thefluorescent body is bonded, and causes the excitation light to enter thefluorescent body, and

a heat-dissipating member to which the lens surface is adhered at leastaround a region to which the fluorescent body is bonded.

(17)

A projector including:

a light source unit that has a light converter, and a light sourcesection that emits excitation light toward the light converter; and

an image-generating section that generates an image on the basis oflight emitted from the light source unit,

the light converter including

a fluorescent body that is excited by excitation light,

a first light-collecting lens that has a lens surface to which thefluorescent body is bonded, and causes the excitation light to enter thefluorescent body, and

a heat-dissipating member to which the lens surface is adhered at leastaround a region to which the fluorescent body is bonded.

This application claims the priority on the basis of Japanese PatentApplication No. 2015-099924 filed on May 15, 2015 with Japan PatentOffice, the entire contents of which are incorporated in thisapplication by reference.

Those skilled in the art could assume various modifications,combinations, subcombinations, and changes in accordance with designrequirements and other contributing factors. However, it is understoodthat they are included within a scope of the attached claims or theequivalents thereof

1. A light converter comprising: a fluorescent body that is excited byexcitation light; a first light-collecting lens that has a lens surfaceto which the fluorescent body is bonded, and causes the excitation lightto enter the fluorescent body; and a heat-dissipating member to whichthe lens surface is adhered at least around a region to which thefluorescent body is bonded.
 2. The light converter according to claim 1,further comprising a reflective layer that is formed at least betweenthe fluorescent body and the heat-dissipating member, and around aregion to which the fluorescent body is bonded in the lens surface. 3.The light converter according to claim 2, further comprising an adhesivelayer that is formed between the reflective layer and theheat-dissipating member.
 4. The light converter according to claim 1,wherein all of the fluorescent body and a region other than a region towhich the fluorescent body is bonded in the lens surface are adhered tothe heat-dissipating member.
 5. The light converter according to claim1, wherein the heat-dissipating member has a stepped part in a convexshape, and the fluorescent body and the lens surface around a region towhich the fluorescent body is bonded are adhered to the stepped part. 6.The light converter according to claim 5, wherein a region outside aregion adhered to the stepped part in the lens surface has a planarshape.
 7. The light converter according to claim 5, wherein a regionoutside a region adhered to the stepped part in the lens surface has acurved surface shape.
 8. The light converter according to claim 5,wherein the heat-dissipating member further has a positioning sectionthat performs positioning of the first light-collecting lens relative tothe heat-dissipating member in a region outside the stepped part.
 9. Thelight converter according to claim 1, further comprising a secondlight-collecting lens that is greater in an outer diameter than thefirst light-collecting lens, and outputs the excitation light toward thefirst light-collecting lens; and a lens holder that holds the secondlight-collecting lens.
 10. The light converter according to claim 9,wherein the first light-collecting lens and the second light-collectinglens are disposed with spacing in between, and space between the firstlight-collecting lens and the second light-collecting lens is structuredto be sealed by the lens holder and the heat-dissipating member.
 11. Thelight converter according to claim 9, wherein a structure is adopted inwhich the first light-collecting lens and the second light-collectinglens are disposed with spacing in between, and a liquid coolant passesthrough space between the first light-collecting lens and the secondlight-collecting lens.
 12. The light converter according to claim 1,wherein a planar size of the fluorescent body is one fifth or less of anouter diameter of the first light-collecting lens.
 13. The lightconverter according to claim 1, wherein the fluorescent body and thelens surface are bonded by normal-temperature bonding or opticalcontact.
 14. The light converter according to claim 1, furthercomprising an output-side lens that is disposed to face the firstlight-collecting lens with the fluorescent body and the heat-dissipatingmember interposed in between, that a fluorescent component emitted fromthe fluorescent body and the excitation light enter, and that has a lenssurface bonded to an output surface of the fluorescent body.
 15. Thelight converter according to claim 14, wherein all of regions other thana region to which the fluorescent body is bonded in the lens surface ofthe first light-collecting lens and the lens surface of the output-sidelens are adhered to the heat-dissipating member.
 16. A light source unitcomprising: a light converter; and a light source section that emitsexcitation light toward the light converter, the light converterincluding a fluorescent body that is excited by excitation light, afirst light-collecting lens that has a lens surface to which thefluorescent body is bonded, and causes the excitation light to enter thefluorescent body, and a heat-dissipating member to which the lenssurface is adhered at least around a region to which the fluorescentbody is bonded.
 17. A projector comprising: a light source unit that hasa light converter, and a light source section that emits excitationlight toward the light converter; and an image-generating section thatgenerates an image on a basis of light emitted from the light sourceunit, the light converter including a fluorescent body that is excitedby excitation light, a first light-collecting lens that has a lenssurface to which the fluorescent body is bonded, and causes theexcitation light to enter the fluorescent body, and a heat-dissipatingmember to which the lens surface is adhered at least around a region towhich the fluorescent body is bonded.